Pull chain mechanism for box mounted lamp holder



D. W. SCOTT Aug. 9, 1960 FULL. CHAIN MECHANISM FOR BOX MOUNTED LAMP HOLDER Filed Nov. 21, 1958 I INVENTOR pom/.0 m saorr ATTORNEYS ijniteci rates atent fines PULL CHAIN MECHANISM FOR BOX MOUNTED LAMP HOLDER Donald W. Scott, Syracuse, N.Y., assignor to Pass & Seymour, Inc., Syracuse, N.Y., a corporation of New York Filed Nov. 21, 1958, Ser. No. 775,601

8 Claims. (Cl. 200-'51.15)

This invention relates to switch mechanism of the socalled pull chain type and more particularly to such switch mechanism as used with lamp holders of plastic, porcelain or the like and especially of the one-piece canopy type.

It is a general object of the present invention to provide a pull chain mechanism of the type defined incorporating improved features facilitating manufacture and assembly as well as effecting a reduction in size.

More particularly it is an object of the invention to fitting about the assembly or center-post rivet and its large diameter end bearing and centered on said dustcover.

An important feature of the invention consists in the simplicity of construction of the several novel parts and their freedom of need for any but the simplest of operations in their manufacture and assembly.

Other and further objects and features of the invention will be more apparent to those skilled in the art upon a consideration of the following specification and accompanying drawing wherein is disclosed a single exemplary embodiment of the invention with the understanding that such changes and modifications may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawing:

Fig. 1 is a rear elevation of a box mounting lamp holder of the mouldedporcelain or plastic type fitted with the improvements of the present invention;

Fig. 2 is a front elevation of the lamp base engaging portion of the lamp holder;

Fig. 3 is an enlarged rear plan of the combined dustcover disc and spring anchor;

Fig. 4 is a diametrical section through the disc of Fig. 3; and

Fig. 5 is a fragmentary section on an enlarged scale of the lamp holder of Fig. 1 taken on broken line 5-5 of that figure representing two diametric planes, viewed in the direction of the arrows of that figure.

As heretofore constructed the pull chain switch components of a lamp holder made primarily of moulded plastic or porcelain construction were complicated in form, required machining operations for their manufacture and an unnecessary number of operations for their assembly. Foremost among the offenders was the center post which acted not only to pivot the switch rotor bridge and the chain actuated driving disc therefor but was called upon to anchor one end of the spring which returns the driving disc. Its manufacture required a number of relatively costly operations and necessitated anon-circular opening in the insulation part and a corresponding shape on the post to prevent relative rotation. The dust-cover required a separate installation pressing operation after the post had been installed and the spring tension adjusted. A number of these operations are eliminated or consolidated by the use of the present construction.

The drawings show the invention associated with a more or less conventional box mounted lamp holder moulded of porcelain and having an extended, box covering flange or base 10 of appropriate diameter and an integral, axial, tubular extension 12 to receive the screw shell contact 14 for engaging a threaded lamp base. This contact and the center one 15 are attached by suitable tubular rivets to the porcelain bottom closure 16 for the extension 12. The part 16 also forms the top closure for the switch well 18 whose circular wall 19 is coaxial with 12. This wall is twice interrupted to pass the terminal straps 20 and 21 radially outwardly to the wiring terminals and a third time for oscillation on the tubular rivet 30 or other standard fastener which forms the center post of the switch. Its preformed head is received loosely in counterbore 31 of through bore 32 in the closure 16 through which the rivet body extends to project entirely through well 18.

The switch bridging member or rotating contactor 34 comprises a central disc bored to rotate on rivet 30 and having a pair of diametrically opposed and axially offset arms 35 adapted to travel in annular channel 36 in the under face of closure 16. The bottom of this channel comprises four ratchet teeth, two opposite ones of which are capped with contacts in the circuit between one of the terminals and the center contact 15 so that when bridged by arms 35 the circuit is closed. Ninety degree rotation of contactor 34 places the arms 35 on nonconducting ratchet teeth faces to open the circuit.

The outer face of the metal contactor disc 34 is formed I with one or more ratchet teeth facing oppositely to those in channel 36 and they in turn cooperate with tooth members on the chain disc.

The arms of bridging member 34 are held down in contact with channel bottom teeth and the teeth on disc 28 are held in contact with those on disc 34 by the compressed conical spring 38 whose small diameter end bears under disc 28 and rotates or slides freely on center rivet 30. The large diameter end of spring 39 is centered on the inwardly pressed portion 40 of dust-cover disc 41 which has its periphery centered in groove 42 in the inner edge of wall 19 forming the switch pocket. Rivet 30 passes through disc 41 and is headed over to hold it tightly in position.

The chain disc 28 is arranged to be oscillated through an arc of slightly more than on each pull and release of the chain, a stop, not shown, limiting the return by engagement with arm 29. In the other direction the enlargement 44 on the chain is stopped against the converging walls at 45.

Return effort is applied to the chain disc by spring 38 as follows. A tangential extension from the small end of the spring has a hooked end 47 engaged about arm 29 while the large end of the spring has a radial extension 48 hooked beneath flap 50 punched and bent up from the rigid plastic material of the dust-cover 41. During astained by having its periphery notched as at 52 in' say sixevenly spaced positions and by providing one or more lugs 53 correspondingly positioned about the disc edge supporting groove 42 to hold the disc in any adjusted position after which the rivet 30 isheaded over at 54 as previously mentioned.

Assembly is achieved by first inserting rivet 30 from the front, assembling the bridging part 34,- 35 overit the well, then the chain disc and chain, then the spring and finally the dust-cover which is rotated clockwise until the proper spring tensionis achieved after which the rivet head 54 is formed to maintain the assembly and adjustment.

The hollow rivet issiinple, cheap and easy to form and assemble but may be replaced by a solid rivet, bolt and nut or a suitable form-of eyelet.

The conical spring can be of less height than a helical one of the required number of turns because of the meet ing possibility of the coils and thus the overall height of the fixture is lessened, reducing packing and shipping costs and required storage space. During rotation of the bridging contact considerable lift is imparted thereto-and thus axial compression of the spring which is facilitated by its shape.

The usual extra operation of applying a dust-cover which must be pressed into place after the center post has been adjusted to tension the spring is combined with as sembling the post parts and effecting the spring tensioning.

The overall cost is considerably lowered.

I claim:

1. In a pull chain type of switch housed in a well of insulating material having stationary switch contacts on the bottom thereof and an opening in said bottom, in" combination, a headed fastener extending through said opening, a contact bridge rotatable on said fastener for cooperation with said contacts, a chain actuated disc oscillatable between limits on said fastener to drive said bridge, a conical spring having its small end secured to the chain disc, a dust-cover for closing said well having a central opening receiving said fastener, means to secure the large end of the spring non-rotatively to said cover; a peripheral seat for said cover in the insulating material surrounding the top of the well, means on said cover and seat whereby to interlock them in each of several relative.

adjusted positions whereby the spring tension may be adjusted by relative rotation of cover andwell housing, and said fastener being secured over said cover to complete the assembly and fix the adjustment.

2. In a pull chain switch housed in a hollow shell having a rigid insulating button therein with a central bore and a concentric groove holding spaced switch contacts, in combination, a headed fastener extending through said bore, a bridging member for said contacts rotatable on said fastener, a manually actuated disc oscillatable on said fastener for driving said bridging member, a spring surrounding said fastener and having one end secured to said disc, a cover for said shell mounted on said fastener and fixed to the other end of said spring, and means on said cover and said insulating shell for interlocking in any of a plurality of selected cover positions to tension said spring.

3. In a pull chain type switch housed in a walled chamber having an insulating base provided with a central through bore, in combination, a headed fastener extending through said bore, stationary contacts on said base, switching mechanism fulcrumed on said fastener and including a biased part, a spring surrounding said fastener and having one end secured to said part, a thin fiat cover for and mounted in a channel in said chamber wall and providing support for the opposite end of said fastener and means struck up from the cover near its outer periphery for attaching the opposite end of said spring thereto.

4'. The combination as claimed in claim 3 in which means on the said cover interlocks in each of several selected positions with means on the chamber wall to hold said cover against rotation after initial adjustment to provide desired spring tension.

5. In a pull chain type of switch housed in a well of material at least the bottom being insulating, and having a hole therethrough, in combination a headed fastener extending through said hole, contacts on said bottom surrounding said fastener, contact mechanism including a contact bridging member and a driving disc therefor pivoted on said fastener, means to rotate said disc between limits, a spring to return said disc, said spring surrounding said fastener, means securing one end of said spring to said disc, a cover closing said well and rotationally adjustable by steps thereon, means securing the other end of said spring to said cover and said fastener passing through the cover to hold it in adjusted position.

6.'The switch of claim 5 in which the spring is conical with the large end bearing on said cover and the small end engaging the disc and holding the contact bridging member against said bottom and contacts.

7. The combination claimed in claim 6 in which said cover has a raised area thereon facing the spring and centering the large end thereof.

8. The combination claimed in claim 6 in which the wire of said spring extends substantially radially from the large end thereof, and a tab struck out from the material of the cover to engage over and hold said radial wire.

References Cited in the file of this patent UNITED STATES PATENTS 987,152 Marshall Mar. 21, 1911 1,007,791 Morey et a1 Nov. 7, 1911 2,364,995 Mueller Dec. 12, 1944 2,545,860 Robertson Mar. 20, 1951 FOREIGN PATENTS 327,512 Germany Oct. 11, 1920 

